JP3449334B2 - Micromachine switch and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micromachine switch and a manufacturing method thereof, and more particularly to a micromachine switch capable of turning on / off a wide signal frequency from DC (direct current) to gigahertz or higher and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, "Microelectromechanical switch" of Yun Jason Yao of Rockwell International Corporation (Japanese Patent Laid-Open No. 9-17300).
The prior art will be described by taking the invention described in 1) as an example.

FIG. 18 shows a plan view (a) of a micromachine switch disclosed in Japanese Patent Laid-Open No. 9-17300 and a sectional view taken along the line EE '. As shown in the figure, an anchor structure 52 made of thermosetting polyimide and a lower electrode 53 made of gold are formed on a substrate 51 made of gallium arsenide.
And a signal line 54 made of gold.

A cantilever arm 55 made of a silicon oxide film is provided on the anchor structure 52. The cantilever arm 55 extends beyond the lower electrode 53 to the position of the signal line 54. It opposes these via a spatial gap.

An upper electrode 56 made of aluminum is provided above the cantilever arm 55 from the anchor structure 52 to the lower electrode 53.
It is manufactured up to the position facing. A contact electrode 57 made of gold is provided below the cantilever arm 55 at a position facing the signal line 54.

In the micromachine switch having such a structure, when a voltage of 30 V is applied between the upper electrode 56 and the lower electrode 53, an electrostatic force attracts the upper electrode 56 in the substrate direction (downward direction of arrow 58). Works.
Therefore, the cantilever arm 55 is deformed toward the substrate side, and the contact electrodes 57 contact both ends of the signal line 54.

In a normal state, as shown in FIG. 19B, a gap is provided between the contact electrode 57 and the signal line 54, so that the two signal lines 54 are separated from each other. Therefore, no current flows through the signal line 54 when no voltage is applied to the lower electrode 53.

However, when a voltage is applied to the lower electrode 53 and the contact electrode 57 is in contact with the signal line 54, the two signal lines 54 are short-circuited and a current can flow between them. Therefore, by applying a voltage to the lower electrode 53, it is possible to control ON / OFF of a current or a signal passing through the signal line 54.

However, in order to reduce the loss of the switch, it is important that the upper electrode 56 and the contact electrode 57 are sufficiently electrically insulated. That is, if the upper electrode 56 and the contact electrode 57 are electrically short-circuited, the signal (including DC) flowing through the signal line 54 also flows out to the upper electrode 56.

Further, even if the upper electrode 56 and the contact electrode 57 are not short-circuited, the AC signal flowing through the signal line 54 still has an AC signal flowing through the signal line 54 when the electrostatic capacitance is considerably large.
It flows to 6 and leaks to the outside. Thus, the upper electrode 56
When the insulation between the contact electrode 57 and the contact electrode 57 is not sufficient, signal leakage becomes large and the switch characteristics deteriorate.

[0011]

However, it has been found that the above-mentioned conventional micromachine switch has the following problems. Turn on the switch (ie,
In order for the contact electrode 57 to contact the signal line 54), a sufficient voltage is applied between the upper electrode 56 and the lower electrode 53 so as to generate an electrostatic force that exceeds the restoring force of the cantilever arm 55. is necessary. At this time, this electrostatic force is inversely proportional to the square of the distance between the upper electrode 56 and the lower electrode 53 (to be exact, the value obtained by subtracting the thickness of the cantilever arm 55 from this distance), so that the distance between the two electrodes is high. It is important to design a small distance.

In the structure of the conventional example, as shown in FIG.
As shown in (b), in addition to the thickness of the cantilever arm 55, the distance between the upper electrode 56 and the lower electrode 53 is larger than the distance between the contact electrode 57 and the signal line 54.
The thickness increases. For example, in order to reduce signal loss in high frequency applications, the thickness of the contact electrode 57 and the signal line 54 needs to be about 2 μm.

Further, when off, the signal line 54 and the contact electrode 57 are
In order to reduce the capacitive coupling with and, it is necessary to have a structure in which both are separated by 4 μm or more. Therefore, the upper electrode 5
6 and the lower electrode 53 are arranged apart from the thickness of the cantilever arm 8 by about 6 μm.

At this time, the area where the upper electrode 56 and the lower electrode 53 overlap is set to 10,000 μm ^2, and the width of the cantilever arm 8 is designed to be 20 μm and the length is designed to be 130 μm.
The inventors of the present application have confirmed that a voltage as high as 00 V is required. Of course, it is also possible to design the cantilever arm 8 so that the restoring force of the cantilever arm 8 is reduced by increasing the length of the cantilever arm 8 or decreasing the width thereof. Alternatively, the cantilever arm 8 may be damaged during the operation of the device.

On the other hand, by enlarging the area where the upper electrode 56 and the lower electrode 53 overlap, a large electrostatic force can be generated and the applied voltage can be reduced, but with this, the entire device becomes large. Will end up. In the conventional example, the applied voltage is reduced by such a method, but this method pays the price that the size of the entire device is obviously increased, and there is a large limit in downsizing the switch.

Since a voltage as high as 100 V is required, it is necessary to improve the film quality of the cantilever arm 8 so that the device will not be destroyed by dielectric breakdown. However, as in the conventional example, the method of forming the cantilever arm 8 of the oxide film on the contact electrode 57 made of gold by the low temperature deposition process (the plasma CVD process at 250 ° C. or lower) provides sufficient withstand voltage characteristics. It is difficult to form a native oxide film.

Further, when the applied voltage becomes high, the electric power consumed in the driving circuit increases, so that the conventional microswitch cannot be applied to an antenna or the like in which a large number of switches are arranged. I understood.

The present invention is intended to solve the above problems, and a main object of the present invention is to provide a micromachine switch that can operate at a driving voltage lower than that of a conventional one and a manufacturing method thereof. Another object of the present invention is to improve the device characteristics by increasing the withstand voltage characteristics of the insulating film in case the applied voltage cannot be lowered.

[0019]

In order to achieve such an object, one mode of a micromachine switch according to the present invention is a first signal line provided on a substrate and a first signal line provided on the substrate. In a micromachine switch for controlling conduction / non-conduction between an end of the first signal line and a second signal line whose end is provided with a predetermined gap, a support provided on the substrate. Member and this support member
Connected to and partly opposite the gap
A beam member provided on the substrate with a space therebetween, a contact electrode provided at a position facing at least the gap on the substrate side of the beam member, and a part of the beam member facing the substrate. A lower electrode provided on the beam member and an intermediate electrode provided on the beam member so as to face the lower electrode, and the areas where the lower electrode faces the intermediate electrode are opposite to each other.
It is composed of a plurality of comb-teeth shaped electrodes .
Alternatively, a supporting member provided on the substrate and the supporting member
So that it is connected to the member and partly faces the gap
A beam member provided on the substrate with a space therebetween,
At least the gap on the substrate side of the beam member
The contact electrodes provided at opposite positions and the front surface on the substrate.
A lower electrode provided so as to face a part of the beam member;
An intermediate electrode provided on the beam member so as to face the lower electrode;
And an upper electrode provided on a part of the beam member
A plurality of comb-teeth-shaped areas that have the same area facing the lower electrode
It is composed of electrodes.

Further, the present invention includes the following constitutions as other embodiments. That is, the beam member is
At least the lower electrode from the connection portion with the support member
The region up to the position facing the is made of a conductive member. Well
Moreover , the conductive member is made of a semiconductor material. The semiconductor material is a single crystal semiconductor. Further, the semiconductor material is an amorphous semiconductor or a polycrystalline semiconductor. Further, the angle formed on the surface of the connecting portion between the supporting member and the beam member is an obtuse angle. Further, the contact electrode is covered with an insulating film that can be capacitively connected to the first and second signal lines.

The substrate is a glass substrate or a ceramic substrate. The substrate is a gallium arsenide substrate. In addition, the conductive portion facing the lower electrode
An upper electrode provided on a part of wood, the intermediate electrode, the upper
The upper electrode is electrically short-circuited and the upper electrode is in an electrically floating state.

[0022] In addition, the micro-machine switch is used in a phased array antenna system. Further, a plurality of support member for supporting the <br/> beam member. Further, the beam member is connected to the support member from the connecting portion of the lower electrode.
The region up to the position facing the pole is formed of a multilayer structure made of at least two kinds of materials.

Next, in the method for manufacturing a micromachine switch according to the present invention, the first signal line provided on the substrate,
A method of manufacturing a micromachine switch for controlling conduction / non-conduction between a second signal line provided on the substrate and having an end portion provided with a predetermined gap from the end portion of the first signal line. A step of forming a lower electrode on the substrate , a supporting member having a predetermined height, and the supporting member
A beam member connected to the beam member , a contact electrode provided on the beam member,
And a step of adhering a member made of an intermediate electrode provided on the beam member on the substrate in a state where the contact electrode faces the gap and is separated from the first and second signal lines. , The lower electrode to the intermediate electrode
To a plurality of comb-teeth-shaped electrodes that have the same area facing each other
Therefore, it is configured . Alternatively, the lower electrode is formed on the substrate.
The forming process, the supporting member having a predetermined height, and the supporting member.
Beam member connected to the holding member, contact provided on the beam member
An electrode and an intermediate electrode provided on the beam member
The member is arranged such that the contact electrode faces the gap.
The base in a state of being separated from the first and second signal lines.
And a step of adhering on a plate, and provided on a part of the beam member
The area of the upper electrode facing the lower electrode is
Is composed of a plurality of comb-teeth-shaped electrodes.

Further, the present invention includes the following configurations as other aspects. That is, the beam member is the support portion.
Facing at least the lower electrode from the connecting portion with the material
The region up to the position is made of a conductive member. Also, the conductivity
The conductive member is formed of a semiconductor material. In addition, the semiconductor
The material is a single crystal semiconductor. Further, the semiconductor material
Is an amorphous semiconductor or a polycrystalline semiconductor. Well
In addition, the connection portion between the support member and the beam member is
It is formed so that the angle formed on the surface is an obtuse angle. Also,
The contact electrode is capacitively connected to the first and second signal lines.
It is covered with a connectable insulator film. In addition, the substrate is
Lath substrate or ceramic substrate. Also, the substrate
Is a gallium arsenide substrate. Also, pair with the lower electrode.
An upper electrode is provided on a part of the conductive member facing
The inter-electrode is electrically shorted to the upper electrode,
The electrodes are in an electrically floating state. In addition,
Chromasin switch is a phased array antenna device
Used for. In addition, a plurality of supports for supporting the beam member
It has a member. Further, the beam member and the support member
Area from the connection part of the to the position facing the lower electrode
Is composed of a multi-layer structure composed of at least two materials
is doing.

As described above, the present invention reduces the drive voltage of the switch by providing the intermediate electrode to substantially shorten the distance between the upper electrode and the lower electrode. For example, an intermediate electrode having the same thickness as the contact electrode is provided on the lower side of the upper electrode with the insulator film interposed therebetween. This intermediate electrode is not directly connected to an external voltage circuit. When a voltage (V) is applied between the upper electrode and the lower electrode, the potential of the intermediate electrode is calculated by the following formula.

V · C ₁ / (C ₁ + C ₂ )

Here, the electrostatic capacitance between the intermediate electrode and the upper electrode is C ₁ , and the electrostatic capacitance between the intermediate electrode and the lower electrode is C.
₂ Since C ₁ is larger than C ₂ , the potential of the intermediate electrode is almost equal to that of the upper electrode.

When this intermediate electrode is applied to the case of the above-mentioned conventional example, the distance between the intermediate electrode and the lower electrode is equal to 4 μm which is the distance between the contact electrode and the signal line. At this time, the distance between the electrodes to which the voltage is applied is substantially 2/3 (= 4
[Μm] / 6 [μm]), the required voltage can be reduced to about 67V, which is 2/3 of the conventional example.

Further, it is noted that the intermediate electrode can be manufactured at the same time as the manufacturing of the contact electrode, and thus has an advantage that the manufacturing cost of the device is not increased at all. The structure of the intermediate electrode can be modified in various ways as will be described in detail in the following embodiments, and each has a great feature.

As described above, according to the present invention, the device characteristics can be improved by driving at a lower applied voltage than the conventional one and by increasing the withstand voltage characteristic of the insulating film.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described.

[First Embodiment] FIG. 1 is a plan view showing a first embodiment of the present invention. As shown in the figure, the micromachine switch includes a support member 7 connected to the signal line 3a and having a cantilever arm 8 and an upper electrode 9, an insulating member 6 connected to the cantilever arm 8, and an insulating property. The contact electrode 5 and the reinforcing member 10 are opposed to each other with the member 6 in between. Cantilever
The beam member is composed of the arm 8, the upper electrode 9, and the insulating member 6.
Composed. The signal line 3 is arranged immediately below the contact electrode 5. An intermediate electrode (not shown) is provided at a position facing the upper electrode 9 via the insulating member 6, and two lower electrodes 4a and 4b are arranged immediately below the intermediate electrode. As shown in FIG. 1, in the present embodiment, the lower electrodes 4a and 4b are separated so that the lower electrode can electrically have two different potentials below the intermediate electrode (not shown). The feature is that

In the structure of this embodiment, the applied voltage is applied between the lower electrodes 4a and 4b, and the supporting member 7 connected to the upper electrode 9 is in an electrically floating state. At this time, half of the voltage applied between the two lower electrodes 4a and 4b acts between the lower electrodes 4a and 4b and the intermediate electrode.

As a result, the voltage that serves as an electrostatic attractive force and is useful for closing the switch is reduced by half.
The switch can be closed by applying twice the voltage as in the case of the above embodiment. On the other hand, the upper electrode 9
Is floating, there is no problem that the insulating member 6 between the upper electrode 9 and the lower electrodes 4a and 4b is broken due to high voltage. And, above all, it is not necessary to connect the signal line 3a for applying a potential to the supporting member 7, and therefore, there is an advantage that wiring of the entire device is greatly simplified.

The method of driving the supporting member 7 in an electrically floating state sometimes causes a problem that it is affected by surrounding wiring (for example, when a large number of switches are arranged, The drive voltage in each switch may be different), and in the present embodiment, the switch can be driven without being greatly affected by the surroundings. Further, in the present embodiment, the example in which the upper electrode 6 is connected to the cantilever arm 8 has been shown, but the potential of the intermediate electrode 15 can be determined by the two lower electrodes 4a and 4b. Can be omitted.
Further, the upper electrode 9 may be simply used as a reinforcing plate, or may be separated from the cantilever arm 8. further,
The support member 7, the cantilever arm 8, and the upper electrode 9 can also be made of a material such as an insulator or a high resistance semiconductor.

[Second Embodiment] FIG. 2 is a plan view showing a second embodiment of the present invention. In the figure, the same reference numerals in FIG. 1 indicate the same or equivalent components. As shown in FIG. 2, in the present embodiment, the lower electrodes 4c and 4d that can electrically have two different potentials below the intermediate electrode 15 have a comb-tooth structure.

In the first embodiment, the switch body 1
When the 4 is bonded, it is necessary to make the portion where the lower electrodes 4a and 4b face each other be located exactly in the middle of the upper electrode 9. That is, unless the overlapping regions of the intermediate electrode 15 and the lower electrodes 4a and 4b have the same size, the potential of the intermediate electrode 15 does not become half of the voltage of the two lower electrodes and is attracted toward the lower electrode having the larger region. May be Then, the cantilever arm 8 may be twisted and displaced.

Therefore, in order to solve such a problem in the present embodiment, the lower electrode has a comb-teeth structure, so that even if a slight deviation occurs when the switch body 14 is bonded, The size of the region overlapping with the upper electrode is made equal. The number of comb teeth is not limited to the illustrated example, and a larger number of comb teeth can be provided. Also, the direction of the comb teeth can be changed arbitrarily. The separation of the electrodes in the embodiments described with reference to FIGS. 1 and 2 is not limited to the lower electrode.
That is, similarly, the upper electrode may be electrically separated into two or more, or both the upper electrode and the lower electrode may be separated. Further, the number of the separated electrodes is not limited to two, and may be plural.

[0039]

[Third Embodiment] FIG. 3 shows a plan view (a) and an AA ′ line sectional view (b) thereof for explaining a third embodiment according to the present invention.
You As shown in the figure, a switch body 14 made of silicon, a lower electrode 4 made of gold, and a signal line 3 made of gold are provided on a glass substrate 1 having a large dielectric constant. A ground plate 2 is formed on the back surface of the substrate 1.

The switch body 14 has a structure in which the support member 7, the cantilever arm 8 and the upper electrode 9 are integrated. Two cantilever arms 8 made of silicon extend from the support member 7 substantially horizontally to the substrate surface. The two cantilevered arms 8 can suppress the rotational movement of the arm to a low level as compared with the single arm in the conventional example, and it is useful for preventing one-sided contact of the switch. However, the number of the cantilever arms 8 may be changed according to the conditions, and the present embodiment includes a structure having one and two or more cantilever arms 8.

By the way, at the connecting portion between the supporting member 7 and the cantilever arm 8, the angles α and β formed on the surfaces thereof are formed.
Are preferably obtuse angles (90 ° <α, β <180 °). By doing so, the strength of the cantilever arm 8 can be increased, and 1M
It enables switching operation at high frequencies such as Hz and above.

An upper electrode 9 made of silicon is provided at the tip of the cantilever arm 8. The upper electrode 9 faces the lower electrode 4 with a spatial gap. The support member 7 is connected to the signal line 3a formed on the substrate 1, and the signal line 3a is electrically connected to the upper electrode 9 via the support member 7 and the cantilever arm 8. .

The insulating member 6 made of an insulating film such as a silicon dioxide film or a silicon nitride film is used as the upper electrode 9
Is provided on the lower surface from the position facing the lower electrode 4 to the position facing the signal line 3. A contact electrode 5 made of gold is provided at a position below the insulating member 6 facing the signal line 3. Similarly, an intermediate electrode 15 is provided on the insulating member 6 so as to face the lower electrode 4.

By providing the insulating member 6 in this way, a short circuit between the contact electrode 5 and the upper electrode 9 can be prevented. However, the insulating member 6 should be provided at least between the contact electrode 5 and the upper electrode 9 and between the intermediate electrode 15 and the upper electrode 9.
It should be between and. When switching a high frequency signal, the surface of the contact electrode 5 may be covered with an insulating film within a range in which the signal line 3 can be capacitively coupled. Conversely, signal line 3
May be covered with an insulating film.

Since the upper electrode 9 having a thickness larger than that of the cantilevered arm 8 is provided above the insulating member 6 facing the contact electrode 5, the contact electrode 5 and the insulating member 6 are separated from each other. It is possible to suppress the warpage due to the distortion generated between the two. Therefore, the contact electrode 5 can be constantly kept parallel to the substrate 1, and an increase in contact resistance due to one-sided contact can be suppressed. In addition, cantilever arm
A beam member is composed of the upper electrode 9, the upper electrode 9, and the insulating member 6.
It

The operation of the micromachine switch shown in FIG. 3 will be described. When a voltage of 70 V is applied between the upper electrode 9 and the lower electrode 4 via the signal line 3a,
An electrostatic force exerts an attractive force on the upper electrode 9 in the substrate direction (downward). Therefore, the cantilever arm 8 bends downward and the contact electrode 5 comes into contact with the signal line 3.

A gap is provided in the signal line 3 at a position facing the contact electrode 5, as shown in FIG. 3 (b). Therefore, current does not flow in the signal line 3 when no voltage is applied, but current can flow in the signal line 3 when voltage is applied and the contact electrode 5 is in contact with the signal line 3. In this way, by applying a voltage to the lower electrode 4, it is possible to control the on / off of the current or signal passing through the signal line 3. When handling a 30 GHz signal, the conventional H
While the insertion loss in the EMT (High Electron Mobility Transistor) switch was 3 to 4 dB, the switch in FIG. 3 obtained a result of 2.5 dB.

As described above, in the micromachine switch of FIG. 3, since the upper electrode 9 is electrically connected to the conductive support member 7 via the conductive cantilever arm 8, a voltage is applied to the upper electrode 9. Can be done easily. However, the upper electrode 9 may be in an electrically floating state. In that case, the signal line 3a is unnecessary, and it is sufficient to apply a voltage to the lower electrode 4 in order to operate the switch.

Further, the support member 7, the cantilever arm 8 and the upper electrode 9 can be made of a semiconductor in which impurities are partially or entirely diffused. In that case, the current flowing between the upper electrode 9 and the lower electrode 4 during the operation of the switch is
Since it is extremely small, it is not necessary to precisely control the content of impurities in these semiconductors.

Further, as described in the manufacturing method below, it is easy to control the thickness of the cantilever arm 8 to be thinner than the other constituent elements. By controlling the thickness of the individual elements in this way, a soft cantilever arm 8 can be produced in a highly rigid component. Therefore, in an element having high rigidity, the deformation at the time of voltage application is performed horizontally with respect to the substrate 1, and most of the deformation is performed by the thin cantilever arm 8. This helps to keep the single contact of the switch low.

However, the upper electrode 9 having the same thickness as the cantilever arm 8 can be included in the present invention. Such a structure has an advantage that the manufacturing method is simplified.

Table 1 shows typical dimensions of the micromachine switch shown in FIG.

[0054]

[Table 1]

[0055] Here, the vertical length relative to the plan view shown in FIG. 3 (a) Width, length FIGS. 3 (a) horizontal length to the plane view of the thickness is 3 The length in the vertical direction is shown in the sectional view of FIG. In addition, the intermediate electrode 15 and the lower electrode 4
The distance between and is 4 μm. However, these dimensions should be designed according to the individual application, and are not limited to the above numerical values. In the present invention, a wide range of designs is possible due to the increased design flexibility. For example, if the thickness of the intermediate electrode 15 is designed to be slightly thinner than that of the contact electrode 5, the contact force between the contact electrode 5 and the signal line 3 increases, and the contact resistance between them decreases. It can be said that this is a design particularly suitable for a switch that turns on / off a DC signal.

If the thickness of the intermediate electrode 15 is designed to be slightly thicker than that of the contact electrode 5, the contact electrode 5 will not come into direct contact with the signal line 3 even when the switch is turned on. However, resistive contact is not always necessary in high frequency applications,
Since it is possible to transmit signals even with capacitive contact,
The contact electrode 5 does not have to directly touch the signal line 3. In this case, since the contact electrode 5 does not touch the signal line 3 directly, mechanical wear can be suppressed to a low level, and there is an advantage that the life of the switch can be kept long.

Further, as a method of driving the switch, an example in which a voltage is applied between the support member 7 electrically short-circuited to the upper electrode 9 and the lower electrode 4 has been shown, but the potential of the support member 7 is not necessarily fixed. Moreover, the operation of the switch is possible only by applying a voltage to only the lower electrode 4. At this time, the potential of the support member 7 (that is, the upper electrode 9) is not fixed and is floating. In such a state, the upper electrode 9 normally has a voltage affected by the surrounding potential, and it is possible to bring the upper electrode 9 into a state close to the ground voltage by disposing a ground line around the upper electrode 9. The ground line is generally arranged near the switch body 14. In this way, when the potential of the supporting member 7 is floated, it is possible to save the labor of providing wiring on the supporting member 7, and there is an advantage that the wiring of the device is simplified as a whole.

Here, the manufacturing process of the micromachine switch according to FIG. 3 will be described with reference to the drawings. Figures 4 and 5
FIG. 4A is a sectional view showing a manufacturing process of the micromachine switch according to FIG. 3; The manufacturing process will be sequentially described.

First, as shown in FIG. 4A, a pattern 1 made of a silicon dioxide film is formed on a substrate 11 made of silicon.
2 to form tetramethylammonium hydroxide (TMA
The substrate 11 is etched by about 6 μm using an etching solution such as H). Here, the substrate 11 is (100)
When silicon having a plane as the main surface is used, the (111) plane becomes a trapezoid exposed on the side surface after etching due to the plane orientation dependence of the etching rate.

Next, as shown in FIG. 4 (b), a new pattern 13 is newly formed on the substrate 1, and the pattern 13 is used as a mask to diffuse boron in a region without a mask, and then deep diffusion of boron is performed. For this purpose, thermal diffusion is performed at 1150 ° C. for about 10 hours, for example. At this time, high-concentration boron is diffused to a depth of about 10 μm. As a result, the support member 7 and the upper electrode 9 are manufactured.

Then, as shown in FIG. 4C, after removing the pattern 13 in the region corresponding to the cantilever arm 8,
Using the remaining pattern 13 as a mask, boron is diffused in the area without the mask. As a result, the switch body 14 including the support member 7, the cantilever arm 8 and the upper electrode 9 is completed. In addition, since boron is shallowly diffused this time,
For example, thermal diffusion is performed at 1150 ° C. for about 2 hours. At this time, high concentration boron is diffused to a depth of about 2 μm.

Next, as shown in FIG. 4 (d), silicon dioxide 1 μm and nitride film 0.05 μm are formed on the upper electrode 9.
An insulating member 6 made of is prepared.

Then, as shown in FIG. 5E, the contact electrode 5 and the intermediate electrode 15 are formed on the insulating member 6 by using gold plating.

Next, as shown in FIG. 5 (f), the substrate 11 thus manufactured is connected to the lower electrode 4 made of gold.
Then, it is placed on the glass substrate 1 on which the signal lines 3 and 3a made of gold are formed. The substrate 1 is manufactured in advance in a step different from the above silicon process. After that, the support member 7 is bonded onto the substrate 1. At this time, an electrostatic bonding technique can be used for bonding the silicon and the glass.

Finally, as shown in FIG. 5 (g), the substrate 1
1 is put into an etching solution having a high boron concentration selectivity such as ethylenediaminepyrocatechol, and the portion where boron is not diffused is dissolved. As a result, a micromachine switch can be manufactured on the substrate 1.

If the substrate 1 is made of ceramic, gallium arsenide or the like, it is possible to bond the support member 7 and these substrates with an adhesive. Alternatively, glass on the surface of these substrates is 2 to 5 μm.
If sputtered for about m, it is possible to use the electrostatic adhesion technique.

By etching the single crystal silicon substrate as described above, the switch body 14 including the cantilever arm 8 and the like is manufactured. By using a single crystal as a material in this manner, there is an advantage that a structure having the most reliable mechanical properties can be manufactured.

Further, since the cantilever arm 8 is made of a single crystal body only, warpage due to the coefficient of thermal expansion does not occur as compared with the structure in which a plurality of materials are bonded together as in the conventional example. That is, by making the changes in the thermal expansion coefficient of the cantilever arm 8 along the direction orthogonal to the surface of the substrate 1 symmetrical with respect to the substrate surface side and the opposite surface side,
The occurrence of warpage is suppressed.

On the other hand, in addition to the method described here, the substrate 1
It is also possible to deposit various thin films on top and utilize selective etching to fabricate a switch having the structure of the present invention. For example, the switch body 14 is not made of single crystal silicon, but is made of amorphous silicon, polysilicon, or a high resistance semiconductor material (GaAs, iron-doped InP, etc.).
You may produce using. The switch body 14 may be made of metal such as gold or aluminum instead of semiconductor.

[0070] [Fourth Embodiment] FIG. 6 is a fourth plan view of the embodiment of (a) and line B-B 'cross-sectional view of the present invention (b) to indicate. As shown in the figure, a support member 7 made of silicon, a lower electrode 4 made of gold, and a signal line 3 made of gold are provided on a glass substrate 1 having a large dielectric constant. A ground plate 2 is formed on the back surface of the substrate 1.

The switch body 14 has a structure in which the support member 7, the cantilever arm 8 and the upper electrode 9 are integrated. Two cantilever arms 8 made of silicon extend from the support member 7 substantially horizontally to the substrate surface. The two cantilevered arms 8 can suppress the rotational movement of the arm to a low level as compared with the single arm in the conventional example, and it is useful for preventing one-sided contact of the switch. However, the number of the cantilever arms 8 may be changed according to the conditions, and the present invention includes a structure having one and two or more cantilever arms 8.

By the way, at the connecting portion between the supporting member 7 and the cantilever arm 8, angles α and β formed on the surface thereof are formed.
Are preferably obtuse angles (90 ° <α, β <180 °). By doing so, the strength of the cantilever arm 8 can be increased, and 1M
It enables switching operation at high frequencies such as Hz and above.

An upper electrode 9 made of silicon is provided at the tip of the cantilever arm 8. The upper electrode 9 faces the lower electrode 4 with a spatial gap. The support member 7 is connected to the signal line 3a formed on the substrate 1, and the signal line 3a is electrically connected to the upper electrode 9 via the support member 7 and the cantilever arm 8. .

The insulating member 6 made of an insulating film such as a silicon dioxide film or a silicon nitride film is used as the upper electrode 9
Starts from the lower surface of the and extends to a position facing the signal line 3. A contact electrode 5 made of gold is provided at a position below the insulating member 6 facing the signal line 3. Similarly, an intermediate electrode 15 is provided on the insulating member 6 so as to face the lower electrode 4. When switching a high frequency signal, the surface of the contact electrode 5 may be covered with an insulating film within a range in which the signal line 3 can be capacitively coupled. Conversely, the signal line 3 may be covered with an insulating film.

A reinforcing member 10 made of silicon is provided above the insulating member 6 facing the contact electrode 5. This is provided in order to suppress warpage due to strain generated between the contact electrode 5 and the insulating member 6 to be small. In this way, by providing the reinforcing member 10,
The contact electrode 5 can be constantly kept parallel to the substrate 1, and the contact resistance can be prevented from increasing due to uneven contact. The reinforcing member 10 is not always necessary depending on the material, film thickness, etc. of the insulating member 6, and a structure without this is also included in the present invention. The cantilever arm 8 and the upper part
A beam member is composed of the electrode 9 and the insulating member 6.

The operation of the micromachine switch shown in FIG. 6 will be described. When a voltage of 30 V is applied between the upper electrode 9 and the lower electrode 4, an electrostatic force exerts an attractive force on the upper electrode 9 in the substrate direction (downward). Therefore, the cantilever arm 8 bends downward and the contact electrode 5 comes into contact with the signal line 3.

A gap is provided in the signal line 3 at a position facing the contact electrode 5, as shown in FIG. 6B. Therefore, current does not flow in the signal line 3 when no voltage is applied, but current can flow in the signal line 3 when voltage is applied and the contact electrode 5 is in contact with the signal line 3. In this way, by applying a voltage to the lower electrode 4, it is possible to control the on / off of the current or signal passing through the signal line 3. When handling a 30 GHz signal, the conventional H
While the insertion loss in the EMT (High Electron Mobility Transistor) switch was 3 to 4 dB, the result of the switch of the present embodiment was 0.2 dB.

Since the upper electrode 9 is electrically connected to the conductive support member 7 via the conductive cantilever arm 8, it is possible to easily apply a voltage to the upper electrode 9. However, the upper electrode 9 may be in an electrically floating state. In that case, the signal line 3a is unnecessary, and it is sufficient to apply a voltage to the lower electrode 4 in order to operate the switch.

Further, the supporting member 7, the cantilever arm 8, the upper electrode 9 and the reinforcing member 10 can be made of a semiconductor in which impurities are partially or entirely diffused. In that case, since the current flowing between the upper electrode 9 and the lower electrode 4 during the operation of the switch is extremely small, it is not necessary to precisely control the content of impurities in these semiconductors.

Further, as described in the following manufacturing method, it is easy to control the thickness of the cantilever arm 8 to be thinner than the other constituent elements. By controlling the thickness of the individual elements in this way, a soft cantilever arm 8 can be produced in a highly rigid component. In the element having a large rigidity, the deformation at the time of applying a voltage is performed horizontally with respect to the substrate 1, and most of the deformation is performed by the thin cantilever arm 8. This helps to keep the single contact of the switch low.

However, the upper electrode 9 and the reinforcing member 10 having the same thickness as the cantilever arm 8 can be included in the present invention. Such a structure has an advantage that the manufacturing method is simplified.

Table 2 shows typical dimensions of the micromachine switch of FIG.

[0083]

[Table 2]

Here, the width is the length in the vertical direction with respect to the plan view of FIG. 6A, the length is the length in the horizontal direction with respect to the plan view of FIG. 4A, and the thickness is as shown in FIG. The length in the vertical direction is shown in the sectional view of FIG. In addition, the intermediate electrode 15 and the lower electrode 4
The distance between and is 4 μm. However, these dimensions should be designed according to the individual application, and are not limited to the above numerical values. In the present invention, a wide range of designs is possible due to the increased design flexibility. For example, if the thickness of the intermediate electrode 15 is designed to be slightly thinner than that of the contact electrode 5, the contact force between the contact electrode 5 and the signal line 3 increases, and the contact resistance between them decreases. It can be said that this is a design particularly suitable for a switch that turns on / off a DC signal.

When the thickness of the intermediate electrode 15 is designed to be slightly thicker than that of the contact electrode 5, the contact electrode 5 does not come into direct contact with the signal line 3 even when the switch is turned on. However, resistive contact is not always necessary in high frequency applications,
Since it is possible to transmit signals even with capacitive contact,
The contact electrode 5 does not have to directly touch the signal line 3. In this case, since the contact electrode 5 does not touch the signal line 3 directly, mechanical wear can be suppressed to a low level, and there is an advantage that the life of the switch can be kept long.

Further, as a switch driving method, an example in which a voltage is applied between the supporting member 7 electrically short-circuited to the upper electrode 9 and the lower electrode 4 is shown, but the potential of the supporting member 7 is not necessarily fixed. Moreover, the operation of the switch is possible only by applying a voltage to only the lower electrode 4. At this time, the potential of the support member 7 (that is, the upper electrode 9) is not fixed and is floating. In such a state, the upper electrode 9 normally has a voltage affected by the surrounding potential, and it is possible to bring the upper electrode 9 into a state close to the ground voltage by disposing a ground line around the upper electrode 9. The ground line is generally arranged near the switch body 14. In this way, when the potential of the supporting member 7 is floated, it is possible to save the labor of providing wiring on the supporting member 7, and there is an advantage that the wiring of the device is simplified as a whole.

Here, the manufacturing process of the micromachine switch according to FIG. 6 will be described with reference to the drawings. 7 and 8
FIG. 7A is a sectional view showing a manufacturing process of the micromachine switch according to FIG. 6. The manufacturing process will be sequentially described.

First, as shown in FIG. 7A, a pattern 1 made of a silicon dioxide film is formed on a substrate 11 made of silicon.
2 to form tetramethylammonium hydroxide (TMA
The substrate 11 is etched by about 6 μm using an etching solution such as H). Here, the substrate 11 is (100)
When silicon having a plane as the main surface is used, the (111) plane becomes a trapezoid exposed on the side surface after etching due to the plane orientation dependence of the etching rate.

Next, as shown in FIG. 7B, a new pattern 13 is newly formed on the substrate 1, and the pattern 13 is used as a mask to diffuse boron into a region without a mask, and then deep diffusion of boron is performed. For this purpose, thermal diffusion is performed at 1150 ° C. for about 10 hours, for example. At this time, high-concentration boron is diffused to a depth of about 10 μm. As a result, the supporting member 7, the upper electrode 9, and the reinforcing member 10 are manufactured.

Next, as shown in FIG. 7C, the pattern 13 in the region corresponding to the cantilever arm is removed, and then the remaining pattern 13 is used as a mask to diffuse boron into a region without a mask. As a result, the switch body 14 including the support member 7, the cantilever arm 8 and the upper electrode 9 is completed. In addition, since boron is shallowly diffused this time, thermal diffusion is performed, for example, at 1150 ° C. for about 2 hours. At this time, high concentration boron is diffused to a depth of about 2 μm.

Then, as shown in FIG. 7D, silicon dioxide of 1 μm is applied from the upper electrode 9 to the reinforcing member 10.
Then, the insulating member 6 made of the nitride film of 0.05 μm is manufactured.

Next, as shown in FIG. 8E, the contact electrode 5 and the intermediate electrode 15 are formed on the insulating member 6 facing the reinforcing member 10 by using gold plating.

Next, as shown in FIG. 8 (f), the substrate 11 thus manufactured is connected to the lower electrode 4 made of gold.
Then, it is placed on the glass substrate 1 on which the signal lines 3 and 3a made of gold are formed. The substrate 1 is manufactured in advance in a step different from the above silicon process. After that, the support member 7 is bonded onto the substrate 1. At this time, an electrostatic bonding technique can be used for bonding the silicon and the glass.

Finally, as shown in FIG. 8G, the substrate 1
1 is put into an etching solution having a high boron concentration selectivity such as ethylenediaminepyrocatechol, and the portion where boron is not diffused is dissolved. As a result, a micromachine switch can be manufactured on the substrate 1.

If the substrate 1 is made of ceramic, gallium arsenide or the like, it is possible to bond the supporting member 7 and these substrates with an adhesive. Alternatively, glass on the surface of these substrates is 2 to 5 μm.
If sputtered for about m, it is possible to use the electrostatic adhesion technique.

By etching the single crystal silicon substrate as described above, the switch body 14 including the cantilever arm 7 and the like is manufactured. By using a single crystal as a material in this manner, there is an advantage that a structure having the most reliable mechanical properties can be manufactured.

Further, since the cantilever arm 8 is made of a single crystal body only, warpage due to the coefficient of thermal expansion does not occur as compared with the conventional structure in which a plurality of materials are bonded together. That is, by making the changes in the thermal expansion coefficient of the cantilever arm 8 along the direction orthogonal to the surface of the substrate 1 symmetrical with respect to the substrate surface side and the opposite surface side,
The occurrence of warpage is suppressed.

On the other hand, in addition to the method described here, the substrate 1
It is also possible to deposit various thin films on top and utilize selective etching to fabricate a switch having the structure of the present invention. For example, the switch body 14 and the reinforcing member 10 may be made of amorphous silicon, polysilicon, or a high-resistance semiconductor material (GaAs, iron-doped InP, etc.) instead of single crystal silicon. The switch body 14 and the reinforcing member 10 may be made of metal such as gold or aluminum instead of semiconductor.

[0099] [Fifth Embodiment] FIG. 9 is a plan view of a fifth embodiment of the present invention (a) and a cross-sectional view of (b) to indicate. As shown in the figure, components having the same reference numerals as those in FIG. 6 indicate that they are the same or equivalent components.

In the micromachine switch shown in FIG. 9 , the insulating member 6b extends from the end face of the upper electrode 9 in FIG.
This is a major difference from the configuration of. This insulating member 6b
Can be formed of an insulating thin film such as an oxide film or a nitride film, but can be formed using the same semiconductor material as that of the upper electrode 9. In that case, for example, a method of lowering the resistance by diffusing impurities only in the supporting member 7 excluding the insulating member 6b, the cantilever arm 8 and the upper electrode 9 using a high-resistance semiconductor material (GaAs, iron-doped InP, etc.). Alternatively, a method of implanting ions such as oxygen into the region of the insulating member 6b to increase the resistance can be used. In the present embodiment, the reinforcing member 10 is provided at a position facing the contact electrode 5, but a structure without this is also included in the present invention.

The reinforcing member 10 may have either low resistance or high resistance. Further, an insulating member 6a is provided below the upper electrode 9 separately from the insulating member 6b. However, this does not contact each other when a voltage is applied between the upper electrode 9 and the lower electrode 4. This is to prevent a short circuit from occurring. The thickness of the insulating member 6a is preferably thinner than that of the contact electrode 5.

Further, in the micromachine switch shown in FIG. 9, the insulating member 6b is located above the substrate 1 as compared with the one shown in FIG. 6, so that a gap between the contact electrode 5 and the signal line 3 is formed. Can be taken large. For this reason, the electrostatic capacitance at the time of off becomes small, and it becomes possible to suppress the leakage current at the time of off.

In the above, the glass substrate has been described as a specific example of the substrate 1. A glass substrate is cheaper than a gallium arsenide substrate and is a promising material for applications such as a phased array antenna that requires integration of a large number of switches. However, the structure of the present invention is not limited to this, and is also effective for gallium arsenide, silicon, ceramics, printed boards, and the like.

The present invention also includes a method of reducing the squeeze effect due to the air existing between the upper electrode 9 and the lower electrode 4 by making a hole in the upper electrode 9. In the present invention, the strength of the insulating member 6b can be easily reinforced by the upper electrode 9 and the reinforcing member 10.
Therefore, even if a plurality of holes are provided inside, the rigidity of the entire movable portion can be kept sufficiently high. Furthermore, if holes are also formed in the insulating member 6b, the contact electrode 5, and the reinforcing member 10 to facilitate the passage of air, the squeeze effect can be significantly suppressed.

[0105] [Sixth Embodiment] FIG. 10 is a Ru sectional view showing a sixth embodiment. In the figure, the same reference numerals in FIG. 3 indicate the same or equivalent components. As shown in FIG. 10, two support members 7 are arranged on the substrate 1 with the signal line 3 interposed therebetween. Therefore, the upper electrode 9 is connected to the cantilever arm 8 extending from each support member 7, and is supported on both sides. Further, in order to generate a sufficient electrostatic force, lower electrodes 4 are provided below the upper electrode 9 at two locations with the signal line 3 interposed therebetween.

As described above, the structure in which the upper electrode 9 is supported by using the plurality of supporting members 7 is also included in the present invention. Also,
The number of support members 7 may be further increased to two or more, and such a structure is also included in the present invention .

[0107] Seventh Embodiment FIG. 11 is a Ru sectional view showing a seventh embodiment. In the figure, the same reference numerals in FIG. 3 indicate the same or equivalent components. As shown in FIG. 11, the switch body 14 has its surface oxidized or the like, so that the cantilever arm 8
Is composed of a silicon layer 8a and a silicon oxide layer 8b sandwiching it from both sides. In this way, if the thicknesses of the silicon oxide layers 8b on both sides are made equal, the thermal expansion coefficients of the substrate 1 side and the opposite side become symmetrical, so that the warp of the cantilever arm 8 is suppressed even if high temperature processing is performed. that.

[0108] [Eighth Embodiment] FIG 12 is a Ru sectional view showing an eighth embodiment. In the figure, the same reference numerals in FIG. 3 indicate the same or equivalent components. As shown in FIG. 12, in the present embodiment, the cantilever arm 8 has a superlattice structure in which thin films made of two or more kinds of materials are alternately laminated. Similar to the above-described seventh embodiment, also in the present embodiment, the coefficient of thermal expansion on the side of the substrate 1 and the coefficient of thermal expansion on the opposite side can be made symmetric, so that the cantilever arm 8 due to temperature change is used.
The warp can be suppressed .

[0109] Ninth Embodiment FIG. 13 is Ru ninth plan view showing an embodiment of (a) and line D-D 'cross-sectional view (b) der of the present invention. 6, the same reference numerals in FIG. 6 indicate the same or equivalent components. As shown in FIG. 13, in the present embodiment, the intermediate electrode 15 is short-circuited to the upper electrode 4 via the embedded wiring 18 in the opening provided in a part of the insulating member 6. Further, the surfaces of the intermediate electrode 15 and the contact electrode 5 are covered with insulating films 16 and 17, respectively, which is a difference from the configuration of FIG.

Since the intermediate electrode 15 is short-circuited with the upper electrode 9, the potential of the intermediate electrode 15 is exactly the same as the potential of the upper electrode 9. The insulator film 16 on the intermediate electrode 15 is provided to prevent the intermediate electrode 15 and the lower electrode 4 from being short-circuited. The insulator film 17 on the contact electrode 5 is symmetrical so that the insulator film 17 and the signal line 3 can come into contact when the insulator film 17 and the lower electrode 3 come into contact with each other (when on). It was installed in.

Here, the short circuit between the intermediate electrode 15 and the upper electrode 9 is caused by the embedded wiring 18 provided in the insulating member 16.
However, it is not limited to this, and the wiring may be provided through the wiring provided at the end of the insulating member 6. Alternatively, the insulating member 6 provided between the intermediate electrode 15 and the upper electrode 9 may be omitted. Good.

It is also possible to provide the insulator films 16 and 17 on a part of the lower electrode 4 and the signal line 3, and such a structure is also included in the present invention. Further, by omitting the insulator film 17 on the contact electrode 5 and making the sum of the thickness of the intermediate electrode 15 and the insulator film 16 thinner than the thickness of the contact electrode 5, the DC signal is turned on / off. A switch for turning off can be manufactured.

Further, the insulating film 16 is omitted, and the thickness of the intermediate electrode 15 is made thinner than the thickness of the contact electrode 5, or the sum of the thickness of the contact electrode 5 and the thickness of the insulating film 17. Also, the short circuit between the intermediate electrode 15 and the lower electrode 4 can be prevented. Further, an insulator film may be provided on both the intermediate electrode 15 and the lower electrode 6. Similarly, an insulator film may be provided on both the contact electrode 5 and the signal line 3. further,
The insulator films 16 and 17 do not need to cover all of the intermediate electrode 4 and the contact electrode 5, and even if they are provided in a part thereof, the effect of the present invention can be obtained.

[Tenth Embodiment] An example in which the micromachine switch according to the first to ninth embodiments is applied to a phased array antenna will be described. As shown below, the above-described micromachine switch can be widely applied from DC to high frequency signals, and is particularly effective when applied to a phased array antenna device.

FIG. 14 is a block diagram showing a phased array antenna device disclosed in Japanese Patent Application No. 10-176367. As shown in the figure, the phased array antenna device has M (M is a natural number of 2 or more) antennas 2
3, the antenna 23 is connected to the phase shift circuit 24. The phase shift circuit 24 includes a data distribution circuit 24a, M data latch circuits 24b connected to the data distribution circuit 24a, and a phase shifter 24c connected to the data latch circuit 24b.

Therefore, each antenna 23 is connected to an N-bit (N is a natural number) phase shifter 24 c, and each phase shifter 24 c is connected to the power feeding unit 21 via the distributor / combiner 22.

The data distribution circuit 24a is also connected to the controller 20. The data distribution circuit 24a and the data latch circuit 24b are realized by thin film transistor circuits (TFT circuits) on the substrate.

The phase shifter 24c is provided with the above-described micromachine switch for each bit, and each data latch circuit 24b is connected to the micromachine switch of each phase shifter 24c. As described above, in the phased array antenna apparatus shown in the same figure, the drive circuit of the phase shifter which has been an external IC in the past is constituted by the TFT circuit, and
And the like are formed in the same layer.

Next, the operation of the phased array antenna device shown in FIG. 14 will be described. Control device 20
Calculates the optimum amount of phase shift for directing the radiation beam in a desired direction with N-bit accuracy based on the preset position of the antenna 23 and the frequency used, and uses the result as a control signal. Output to the data distribution circuit 24a. The data distribution circuit 24a distributes a control signal to each data latch circuit 24b.

The radiation direction of the radio wave in the antenna 23 is
All antennas 23 can be switched at once. At that time, each data latch circuit 24b rewrites the held data into a control signal that is input data in synchronization with the timing signal for switching the beam direction, and requires the phase shifter 24c based on the held data (control signal). The driving voltage is simultaneously applied to the micromachine switches of the bits.

When a driving voltage is applied to the micromachine switch, the micromachine switch closes the circuit and turns on the bit including the micromachine switch. Then, the phase shift amount of the phase shifter 24c is set depending on which bit of the phase shifter 24c is turned on.

Each phase shifter 24c changes the phase of the high frequency signal by the amount of phase shift set in this way, and each antenna 2
Power 3 Then, each antenna 23 radiates a phase corresponding to the feeding phase, and the radiation is generated by an equiphase surface, thereby forming a radiation beam in a direction perpendicular to the equiphase surface.

Next, the detailed structure of the phased array antenna device according to FIG. 14 will be described. FIG. 15 is an exploded perspective view showing the phased array antenna device.
As shown in the figure, the overall structure is a multilayer structure. That is, the distribution / synthesis layer L1, the dielectric layer L2, the power feeding slot layer L3, the dielectric layer L4, and the layer (hereinafter referred to as the phase shift circuit layer) L5 including the radiation element, the phase shifter, and the TFT circuit. And the dielectric layer L6 and the parasitic element layer L7 are closely adhered to each other.

Each layer is made into a multi-layer by utilizing the photolithography and etching technique, the adhesion technique and the like. For example, the parasitic element layer L7 and the phase shift circuit layer L5
Is for the metal film formed on each surface of the dielectric layer L6,
It is formed by performing photolithography and etching techniques. The power feeding slot layer L3 is formed by subjecting the metal film formed on one surface of the dielectric layer L4 to photolithography and etching techniques.

A plurality of parasitic elements 32 are formed on the parasitic element layer L7. This parasitic element 32 is
Used to widen the band of the antenna, the dielectric layer L6
Is electromagnetically coupled to the radiating element of the phase shift circuit layer L5 via. A dielectric material having a relative dielectric constant of about 2 to 10 is used for the dielectric layer L6. For example, if glass is used, the manufacturing cost can be reduced, and it is desirable to use glass for at least one of the dielectric layers. If the problem of manufacturing cost is ignored, a dielectric material such as alumina having a high relative dielectric constant or foam material having a low relative dielectric constant may be used for the dielectric layer L6.

Next, in the phase shift circuit layer L5, a part of the antenna 23 shown in FIG. 12, a phase shift circuit 24, a strip line for feeding the antenna 23, and the like are formed.

Next, the dielectric layer L4 is formed of a dielectric material such as alumina having a relative dielectric constant of about 3-12. Next, the power feeding slot layer L3 is made of a metal having conductivity and is a power feeding slot 3 which is a power feeding coupling means.
A plurality of 0s are formed. The power supply slot layer 30
Is connected to the phase shift circuit layer L5 through a through hole that is appropriately provided in the dielectric layer L4, and functions as the ground of the phase shift circuit layer L5.

Next, a plurality of distribution / combiners 22 are formed in the distribution / combination layer L1. The distributor / combiner 22 is electromagnetically coupled to the phase shift circuit layer L5 through the feeding slot 30 provided in the feeding slot layer L3. One distribution / combiner 22 and one power supply slot 30 form one power supply unit, and each unit is arranged in a matrix. However, those not arranged in a matrix are also included in the present invention.

The radiating elements 32 may be arranged in a matrix or simply two-dimensionally arranged. Alternatively, they may be aligned in one direction. Further, in FIG. 15, the distribution combiner 22 and the phase shift circuit layer L5 are electromagnetically coupled to each other via the feeding slot layer L3, but the distribution combiner 22 and the phase shift circuit layer L5 are connected to the feeding pin or the like. When they are connected by another power supply coupling means, they may be formed on the same surface.

Next, the phase shift circuit layer L5 shown in FIG. 15 will be described in detail. FIG. 16 shows 1 of the phase shift circuit layer L5.
It is a top view which shows a unit. As shown in the figure, the radiating element 41 and the phase shifter group 4 are provided on the dielectric layer L6 such as a glass substrate.
0 and a data latch circuit 46 are formed. However, the data latch circuit 46 is provided for each bit of the phase shifters 40a to 40d.

Further, the strip line 42 is arranged from the radiating element 41 through the phase shifter group 40 to a position corresponding to the power feeding slot 30 shown in FIG. Then, as the radiating element 41, for example, a patch antenna,
A printed dipole, slot antenna, aperture element, etc. are used. As the stripline 42, a distributed constant line such as a microstrip line, a triplate line, a coplanar line, or a slot line is used.

The phase shifter group 40 shown in FIG. 16 constitutes a 4-bit phase shifter as a whole, that is, four phase shifters 40a, 40b, 40c and 40d. Each of the phase shifters 40a to 40d can change the phase to be fed by 22.5 °, 45 °, 90 ° and 180 °, and is composed of a strip line and a micromachine switch.

Here, the phase shifters 40a-40c are composed of two strip lines 44 connected between the strip line 42 and the ground 43, and a micromachine switch 45 connected in the middle of the strip line 44. Has been done. These phase shifters form a loaded line type phase shifter.

On the other hand, in the phase shifter 40d, the micromachine switch 45 connected in the middle of the strip line 42.
a, a U-shaped strip line 44a, and a micromachine switch 45a connected between the strip line 44a and the ground 43. This phase shifter constitutes a switched line type phase shifter.

Generally, when the phase shift amount is small, the loaded line type has better characteristics, and when the phase shift amount is large, the switched line type has better characteristics.
Therefore, the loaded line type is used as the 22.5 °, 45 ° and 90 ° phase shifters, and the switched line type is used as the 180 ° phase shifter. Of course, the phase shifter 40
It is also possible to use a switched line type for a to 40c.

The two micromachine switches (45 or 45a) included in each of the phase shifters 40a to 40d are connected to the data latch circuit 46 arranged in the vicinity thereof, and are driven by the drive voltage output from the data latch circuit 46. Work at the same time. In this way, the feeding phase of the high frequency signal flowing through the strip line 42 is changed by the function of the phase shifter group 40.

Instead of arranging the data latch circuit 46 in the vicinity of each micromachine switch, a plurality of data latch circuits are collectively arranged in one place, and wiring is extended from there to drive each micromachine switch. May be. Also, one data latch circuit may be connected to a plurality of different units of micromachine switches.

FIG. 17 is an enlarged plan view of the periphery of the micromachine switch 45 used in the loaded line type phase shifter. As shown in the figure, the two micromachine switches 45 are arranged symmetrically with respect to the two striplines 44. Further, these micromachine switches 45 are connected to one data latch circuit (not shown), and a drive voltage (external voltage) is simultaneously supplied from the data latch circuit. Of course, as the micromachine switch 45, the one described in the first to seventh embodiments can be used.

[0139]

As described above, the present invention has the intermediate electrode between the lower electrode and the upper electrode of the beam member. Therefore, by providing such an intermediate electrode, the applied voltage for driving the switch can be reduced. For example, when the contact electrode and the signal line have a gap of 4 μm, the voltage can be reduced to about 2/3 that of the conventional example. Further, when the distance between the contact electrode and the signal line is 4 μm or less, the effect of reducing the applied voltage is further increased,
It is easy to reduce the amount to 1/2 or less of the conventional example.

Since this intermediate electrode can be manufactured at the same time as the conventional contact electrode is manufactured, there is no need to add an additional step to the switch manufacturing process, and the cost increase can be suppressed. . Further, since the applied voltage can be reduced, it is possible to prevent a large voltage from being applied to the insulator film between the upper electrode and the lower electrode, and it is not necessary to produce a particularly high-quality insulator film. This leads to widening the selectivity of the manufacturing process. Therefore, it is possible to prevent the breakdown of the device which has conventionally been caused by the limit of the withstand voltage characteristic of the insulator film. In addition, the voltage required by the external drive circuit also drops,
At the same time as the structure was simplified, the power consumption was also reduced.

On the other hand, by providing two lower electrodes,
When compared with the structure having the same size and one lower electrode, the applied voltage becomes higher, but the voltage is not applied to the insulating film, so that dielectric breakdown does not occur even if a low quality insulating film is used. The increase in applied voltage can be compensated by increasing the size of the device and can be employed in applications where the device size does not need to be particularly small. Above all, the presence of the upper electrode is not necessary, and the switch can be driven only by applying a voltage to the lower electrode, which brings about a remarkable effect that the wiring of the switch is simplified. Therefore, defects such as an increase in cost associated with wiring, a complicated device structure, and a decrease in long-term reliability are remarkably improved.

In addition, since the switch manufacturing process according to the present invention can use a high temperature process, the following effects can be obtained: 1) The selection of materials for the beam member and the like is widened, and various conductors and semiconductors can be used. It is possible to use it and increase the degree of freedom in material selection. 2) The electrical characteristics of the device are improved because the insulator film manufactured at high temperature has excellent withstand voltage characteristics. 3) Since the degree of freedom in the thickness direction is increased, the width of the beam member can be reduced and the size of the switch can be reduced.

Because of the above advantages, the micromachine switch according to the present invention is not limited to a simple switch that is used by separating it into individual pieces, but it is required that the micromachine switch be integrated on a large-area substrate in the order of tens of thousands. It enables new applications such as phased array antennas.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

FIG. 2 is a plan view showing a second embodiment of the present invention.

FIG. 3 is a plan view (a) showing a third embodiment of the present invention and a sectional view (b) taken along the line AA ′.

FIG. 4 is a cross-sectional view showing a manufacturing process of the micromachine switch according to FIG.

FIG. 5 is a cross-sectional view showing the manufacturing process following that of FIG. 4;

FIG. 6 is a plan view (a) and a sectional view (b) taken along line BB ′ of the fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a manufacturing process of the micromachine switch of FIG.

FIG. 8 is a cross-sectional view showing the manufacturing process following that of FIG. 7;

FIG. 9 is a plan view (a) showing a fifth embodiment of the present invention and a cross-sectional view (b) taken along the line CC ′ thereof.

FIG. 10 is a sectional view showing a sixth embodiment.

FIG. 11 is a cross-sectional view showing a seventh embodiment.

FIG. 12 is a sectional view showing an eighth embodiment.

FIG. 13 is a plan view (a) and a DD ′ line cross-sectional view (b) showing a ninth embodiment of the present invention.

FIG. 14 is a block diagram showing a phased array antenna device (the tenth embodiment of the present invention).

FIG. 15 is an exploded perspective view showing a detailed configuration of the phased array antenna device according to FIG.

16 is a plan view showing a phase shift circuit according to FIG.

FIG. 17 is a plan view showing the periphery of the micromachine switch according to FIG.

FIG. 18 is a plan view (a) showing the conventional example and its E-
It is an E'line sectional view (b).

[Explanation of symbols]

1 ... Board, 2 ... Ground plate, 3, 3a ... Signal line, 4, 4
a, 4b, 4c, 4d ... lower electrode, 5 ... contact electrode, 6,
6a, 6b ... Insulating member, 7 ... Supporting member, 8 ... Cantilever arm, 8a ... Silicon layer, 8b ... Silicon oxide layer, 9 ...
Upper electrode, 10 ... Reinforcing member, 11 ... Substrate, 12, 13 ...
Pattern, 14 ... Switch body, 15 ... Intermediate electrode, 1
6, 17 ... Insulator film, 18 ... Embedded wiring, 20 ... Control device, 21 ... Feed unit, 22 ... Distribution combiner, 23 ... Antenna, 24 ... Phase shift circuit, 24a ... Data distribution circuit, 24b
... data latch circuit, 24c ... phase shifter, 30 ... power feeding slot, 31 ... phase shifting circuit, 32 ... parasitic element, 40 ... phase shifter group, 40a, 40b, 40c, 40d ... phase shifter, 4
1 ... Radiating element, 42 ... Strip line, 43 ... Ground,
44, 44a ... Strip line, 45, 45a ... Micromachine switch, 46 ... Data latch circuit, L1 ...
Distribution combining layer, L2, L4, L6 ... Dielectric layer, L3 ... Feed slot layer, L5 ... Phase shift circuit layer, L7 ... Parasitic element layer.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-213191 (JP, A) JP-A-11-204013 (JP, A) JP-A-4-370622 (JP, A) JP-A-8- 213803 (JP, A) JP 10-149757 (JP, A) JP 9-17300 (JP, A) JP 5-242788 (JP, A) JP 8-509093 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01H 59/00

Claims (28)

(57) [Claims] 1. A first signal line provided on a substrate, and a second signal line provided on the substrate and having an end portion with a predetermined gap from the end portion of the first signal line. In a micromachine switch for controlling conduction / non-conduction with a signal line, a support member provided on the substrate and a part of the support member connected to the support member and facing the gap.
A beam member provided on the substrate with a space therebetween, a contact electrode provided at a position facing at least the gap on the substrate side of the beam member, and the contact electrode provided on the substrate. A lower electrode provided to face a part of the beam member, and an intermediate electrode provided to the beam member so as to face the lower electrode, and the areas where the lower electrode faces the intermediate electrode are mutually
A micromachine switch characterized by being composed of a plurality of equal comb-shaped electrodes . 2. A first signal line provided on a substrate, and
Provided on the substrate and from the end of the first signal line.
With a second signal line that is provided at the end with a fixed gap
Switch for controlling conduction / non-conduction between
In, the support member provided on the substrate and a part of the support member connected to the support member and facing the gap.
Beam member provided on the substrate with a space therebetween
And at least the gap on the substrate side of the beam member.
Contact electrode provided at a position facing the bottom of the beam member, and a contact electrode provided on the substrate facing a part of the beam member.
And Part electrodes, intermediate potential, which is provided to face the lower electrode to the beam member
And a pole, the lower electrode and the upper electrode provided on a portion of said beam member
To a plurality of comb-teeth-shaped electrodes that have the same area facing each other
Therefore , a micromachine switch characterized by being configured . 3. The beam member according to claim 1 , wherein the beam member is at least connected to the support member.
Also, the region up to the position facing the lower electrode is a conductive member.
Micromachine switch characterized by consisting of . 4. The micromachine switch according to claim 3 , wherein the conductive member is made of a semiconductor material . 5. The micromachine switch according to claim 4 , wherein the semiconductor material is a single crystal semiconductor . 6. The semiconductor material according to claim 4 , wherein the semiconductor material is an amorphous semiconductor or a polycrystalline half.
A micromachine switch characterized by being a conductor . 7. The connecting portion between the supporting member and the beam member according to claim 1 or 2 ,
A micromachine switch characterized by an obtuse angle . 8. The method of claim 1 or 2, wherein the contact electrode, the first and second signal lines and the capacitance contact
A micromachine switch characterized by being covered with a continuous insulating film . 9. The micromachine switch according to claim 1 or 2 , wherein the substrate is a glass substrate or a ceramic substrate . 10. The micromachine switch according to claim 1 or 2 , wherein the substrate is a gallium arsenide substrate . 11. The upper electrode according to claim 3 , wherein a part of the conductive member facing the lower electrode has an upper electrode.
A micromachine switch , wherein a pole is provided, the intermediate electrode is electrically short-circuited with the upper electrode, and the upper electrode is in an electrically floating state . 12. The micromachine switch according to any one of claims 1 to 3 , wherein the micromachine switch is a phased array antenna.
A micromachine switch characterized by being used in a tena device . 13. A micromachine switch according to any one of claims 1 to 3 , further comprising a plurality of support members that support the beam member . 14. The odor according to any one of claims 1 to 3.
The beam member is connected to the support member from the connecting portion to the lower portion.
At least two types of regions up to the position facing the electrode
A multi-layered structure made of materials
Micromachine switch . 15. A first signal line provided on a substrate,
From the end of the first signal line provided on the substrate
A second signal line having an end portion separated by a predetermined gap
A micromachine switch that controls conduction / non-conduction between
In the manufacturing method of H, a step of forming a lower electrode on the substrate , a supporting member having a predetermined height, and connecting to the supporting member
Beam member, contact electrode provided on the beam member, and
Contact the member consisting of the intermediate electrode provided on the beam member
An electrode is opposite the gap and the first and
A process for adhering on the substrate in a state of being separated from the second signal line.
And the areas where the lower electrodes face the intermediate electrodes are
Characterized by being composed of a plurality of equal comb-shaped electrodes
And a method for manufacturing a micromachine switch . 16. A first signal line provided on a substrate,
From the end of the first signal line provided on the substrate
A second signal line having an end portion separated by a predetermined gap
A micromachine switch that controls conduction / non-conduction between
In the manufacturing method of H, a step of forming a lower electrode on the substrate , a supporting member having a predetermined height, and connecting to the supporting member
Beam member, contact electrode provided on the beam member, and
Contact the member consisting of the intermediate electrode provided on the beam member
An electrode is opposite the gap and the first and
A process for adhering on the substrate in a state of being separated from the second signal line.
The upper electrode provided on a part of the beam member and the lower electrode.
A plurality of comb-shaped electrodes facing area is equal to physicians each other in
Therefore, a method of manufacturing a micromachine switch, which is configured as described above. 17. The method of claim 15 or 16, wherein the beam member, the less the connection portion between the support member
Also, the region up to the position facing the lower electrode is a conductive member.
A method of manufacturing a micromachine switch, comprising: 18. The method for manufacturing a micromachine switch according to claim 17 , wherein the conductive member is formed of a semiconductor material . 19. The method of manufacturing a micromachine switch according to claim 18 , wherein the semiconductor material is a single crystal semiconductor . 20. The semiconductor material according to claim 18 , wherein the semiconductor material is an amorphous semiconductor or a polycrystalline half.
A method for manufacturing a micromachine switch, which is characterized by using a conductor . 21. The connecting portion between the supporting member and the beam member according to claim 15 , wherein the surface is provided with a connecting portion between the supporting member and the beam member.
A method for manufacturing a micromachine switch, which is characterized in that the angle formed in the switch is an obtuse angle . 22. The contact electrode according to claim 15 , wherein the contact electrode is capacitively connected to the first and second signal lines.
A method of manufacturing a micromachine switch, characterized by covering with a continuous insulating film . 23. The method of manufacturing a micromachine switch according to claim 15 , wherein the substrate is a glass substrate or a ceramic substrate . 24. The method of manufacturing a micromachine switch according to claim 15 , wherein the substrate is a gallium arsenide substrate . 25. The upper electrode according to claim 17 , wherein a part of the conductive member facing the lower electrode has an upper electrode.
A method of manufacturing a micromachine switch , wherein a pole is provided, the intermediate electrode is electrically short-circuited with the upper electrode, and the upper electrode is in an electrically floating state . 26. The micromachine switch according to any one of claims 15 to 17 , wherein the micromachine switch is a phased array antenna.
A method for manufacturing a micromachine switch, which is used for a tenor device . 27. The method according to any one of claims 15 to 17.
And a plurality of supporting members for supporting the beam member are provided.
Manufacturing method of micromachine switch. 28. The method according to any one of claims 15 to 17.
The beam member is connected to the support member from the lower portion to the lower portion.
At least two types of regions up to the position facing the electrode
A multi-layered structure made of materials
Manufacturing method of micromachine switch.